Lotjd speaker motor



May 26, 1931. c. w. PETERSON 1,806,914

LOUD SPEAKER MOTOR Filed March 7, 1930 l N VEN TOR.

A TTORNE Y.

Patented May 26, 1931 PATEN T [OFFICE CHARLES W. PETERSON, OF CINCINNATI, OHIO LOUD srEAKER'MoroR Application filed March 7, 1930. Serial No.- 433,958.

My-invention relates to loud speaker motors of the type in which the armature moves in a path axial of the field in which 1t1s located, and has particular reference to the mechanical structure of the device. In my application Serial No. 343,735, filed March 1, 1929, which has matured into patent No. 1,797 ,965, March 24, 1931, I have shown and described a loud speaker motor in which two annular air gaps are provided which are subject to a magnetlc field, with an armature having two ring-shaped paramagnetic members located in saidv air gaps and held normally slightly out of registry therewith. It is the object of my present construction to provide an improvement on the mechanical construction of the device of my said co-pending application.

It is my object to provlde astructure having a minimum number of parts and of the simplest possible'assembly It s my ob e ct to provide a construction in which the field coil and the armature excltlng 0011 are formed in chambers into'which they can be readily dropped in the act of assembling the device. It is also my ob]ect to prov de a simple but adequate method of mechanically holding the armature so that 1t 1s largely free of any tendency to strlke agalnst the pole pieces, audit is my ob ect to make the various magnetic parts of s1mple metal stampings secured together in the slmplest possible manner.

a v I accomplish my objects by that certain construction and arrangement of parts of which typical examples are shown in the "drawings and will be described, and the nov- 7 elty of the same duly claimed.

In the drawings Figure 1 is :a central cross-section of a device built in accordance with my invention.

Figure 2 is a like view showing a somewhat modified construotion. 1

Figure 3 is a top plan view of the armature. l

Figure 4 is a ture.

' The main body portion of my device is sorformed of a metal cup 1 which is flanged as side elevation of the arma- '41& that form the poles of'the magnetic system. These poles can be readily formed on the device with exact spacing and the core held flush with the base of the cup with a screw 5. Dropped into the cup so as to surround the core is the field coil 6 which will be suppliedwith a steady electric current.

In the form shown in-Figure 1, I provide for two shallow cup-shaped discs 7 having flanges 8, both of these cup-shaped discs being alike so as to out down the number of different parts required in the mechanism. There will be registering holes punched in the flanges 2, 88, so that bolts 9 can be used to secure the cup shaped plates to the main cup. Mounted in the spacing between the two cup-shaped plates which in assembling are mounted face toface,is set the coil 10 which supplies the fluctuating current for energizing the armatures. V

The armature itself consists of two light rings 12-12 of paramagnetic material connected by a series of light weight pins which may be of wood or some other nonmagnetic material. The cup-shaped discs. are cut with apertures which result in forming annular holes 13-13 when the assembly is put together, said. holes 1313'surroundingand actually registering with the polts l4 onthe core. p

The spacing of the armature rings 12-12 may be slightly less or slightly greater than the spacing between the two air gaps formed between the poles 4. l and 1313. Soldered to the outer armature ring 12 are two supporting springs 15-15, and soldered to the inner armature ring, but in opposite position tothe springs 1515, are springs 16-16. The two cup-shaped discs have tongues 11 which are struck up from thesaid discs in proper'position tobe pinned to the outer ends of the springs 15-15 and the springs 1616.

In assembling-this device, the core is fastened to the bottom of the cup and the coil dropped in place. The two cup-shaped discs are then assembled over the energizing coil and temporarily clipped together, whereupon the armature is set in place and the springs 15-45 and 1616 are fastened to the tongues of the two discs which will then be in proper position. The two cupshaped discs are then mounted on the flange of the main cup and bolts 5) inserted, and the construction has been completed.

Instead of using two shallow cupped plates as at 7, it is relatively as advantageous to use one deep cup-shaped plate 17 (Figure 2) and one flat disc 18. In the modification of Figure 2, the structure is so shown, and in this instance the tongues are retaining the armature mounting springs at the inner end thereof are struck up from the flat disc 18. The depth of the cup in the disc 17 will be such as to house the energizing coil.

In making up the armature, it is desirable, in preventing the armature itself to build up excessive vibratory movement at periods which are resonant with the structure of the armature, to wrap the frame that supports the two ring-shaped members with thread, as indicated at 19. This thread will serve as a damper to prevent the armature from setting up its own period of vibration, thus distorting the sounds transmitted from it to accentuate some at the expense of others.

I have indicated a diaphragm 20 of conical shape, which is connected to a spider 21 forming part of the frame of the armature structure.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a motor structure for the purpose described, a flanged cup, a pole piece secured to the base of the cup, and having annular ridges thereon to form field poles, at field coil housed in the cup around said pole piece, a pair of plates shaped so that when set together a chamber is left between them, said plates having centrally located apertures, the walls of which form outer poles adjacent the above noted ridges, an energizing coil housed in the chamber be tween the plates, said plates being secured to the flange of the cup and in magnetic relation thereto.

2. In a motor structure for the purpose described, a flanged cup, a pole piece secured to the base of the cup, and having annular ridges thereon to form field poles, a field coil housed in the cup around said pole piece, a pair of plates shaped so that when set together a chamber is left between them, said plates having centrally located apertures, the walls .of which form outer poles adjacent the above noted ridges, an energizing coil housed in the chamber between the plates, said plates being secured to the flange of the cup and in magnetic relation thereto, an armature comprising spaced rings located in the annular air gaps so established, and mounting elements secured to the armature, and projections on the plates attached thereto.

3. In a motor structure for the purpose described, a flanged cup, a pole piece secured to the base of the cup, and having annular ridges thereon to form field poles, a field coil housed in the cup around said pole piece, a pair of plates shaped so that when set together a chamber is left between them, said plates having centrally located apertures, the walls of which form outer poles adjacent the above noted ridges, an energizing coil housed in the chamber between the plates, said plates being secured to the flange of the cup and in magnetic relation thereto, said plates being formed each as shallow flanged cups, whereby when same are placed together the said chamber is provided.

4. An armature structure designed for movement axially within two magnetic air gaps of annular shape under influence of an oscillatory flux in the poles about said gap, comprising permeable rings, a frame joining said rings in proper spacing, and means for damping vibrations self-accentuated in the said armature.

5. An armatune structure designed for movement axially within two magnetic air gaps of annular shape under influence of an oscillatory flux in the poles about said gap, comprising permeable rings, a frame joining said rings in proper spacing, and means for damping vibrations self-accentuated in the said armature, said means comprising a wrapping of relatively non-vibratory nature mounted about the said frame.

6. An armature structure designed for movement axially within two magnetic air gaps of annular shapeunder influence of an oscillatory flux in the poles about said gap, comprising premeable rings, a frame joining said rings in proper spacing, and means for damping vibrations self-accentuated in the said armature, and means for mounting the said armature comprising a pair of resilient arms at one end of the frame joining the two rings, and a like pair opposite to said first pair and at the opposite end of the frame, and mounting means to which i said arms are secured whereby the tendency of said armature to move in other than a path axial of the annular air gaps is reduced.

7. In a motor structure for the purpose described, a flanged cup, a cylindrical center pole secured to the base of the cup, a field coil housed in the cup around said center pole, a pair of plates shaped so that when set together a chamber is left between them, 

